I only do this routine 2-3 times every 2 months. The reasoning for this is so my arms do not get out of proportion with the rest of my body.
Here is a sample of my routine:
Monday - chest
Tuesday - shoulders
Wednesday - legs
Thursday - arms
Friday - back
Notice I do my arms on Thursday. This is the day I do my normal arm workout. On Monday I will add this extra arm workout. That way my arms have 2 full days to recover for my normal arm workout.
After I finish my chest workout my arms are already warm so I jump right in.
Pick 3 exercises for biceps, 3 for triceps and 3 for forearms.
My routine is usually like this:
Biceps - Barbell curl, Dumbbell curl, Preacher curl
Triceps - Skull crushers, Pushdowns, 1 arm overhead push
Forearms - Hammer curls, Reverse curls, Wrist curls
All of these exercises are to be a superset for 1 set only. Go to failure on each set then do one more. Make sure you move through to the next exercises quickly to achieve the maximum pump. I will usually get all the equipment ready so I can move more quickly. On each rep make sure you use strict form. Make the contraction last 2 seconds and the negative 4 seconds. You must follow these rules to achieve maximum results. Just do one giant set to failure and you are finished. Go super intense. Your arms will feel like they are 20" when you're done.
I just call this my "Extra Arms Routine". It's worked for me pretty well and I really think it will work for you. Good luck!